Incidental discovery of an adrenal mass during radiologic examinations is common. Several recommendations have been made for the management of so-called incidentalomas. It has become clear that not all incidentalomas should be operated, but the criteria for nonoperative treatment have been under continuous debate. In this study 36 operated incidentalomas are presented, and the indications for operative treatment are discussed with a review of the recent literature on the subject. Four pheochromocytomas and three hormonally active cortical adenomas, two producing cortisol and one androgens, were found. In this series there were no malignancies. The operation could have been avoided in most cases, and patients could have been followed up with repeated radiologic examinations. It is suggested that masses smaller than 6 cm in diameter be followed radiologically after 3, 9, and 18 months. Masses between 3 and 6 cm could be further examined using magnetic resonance imaging and fine needle aspiration and then operated if features suggestive of malignancy are found. Masses larger than 6 cm in diameter should be treated operatively.